YoungMath and Expert Subjects.com Present Algebra I: Variables

Lesson Objectives (A.3a;A.3b): Define the purpose of Algebra Define Algebra Define variable Define algebraic expression Define algebraic equation

“Algebra looks so hard!” Why am I learning this? Algebra is everywhere! Teaches organization Simple way of expressing a question to enable you to find the answer faster Sharpen your reasoning (problem solving) skills Prepare your for higher learning “Algebra looks so hard!”

What is algebra? Examples: The part of mathematics in which letters and other symbols are used to represent unknown numbers and quantities in formulas and equations. Examples: If there are 4,000 widgets in a mile, how long is a widget (in inches)? 2. If the temperature outside is 25° F, what is the temperature in degrees Celsius?

What is the unknown value? What’s the unknown in example 1? Length of a widget in inches What is the unknown in example 2? Temperature in degrees Celsius In algebra, we use variables to represent unknown values. Variable: *A symbol (frequently a letter) used to represent an unknown value; An element, feature, or factor that is liable to vary or change

Expressions vs. Equations Question: What is the difference between a expression and an equation? Language Arts- phrase and a sentence Phrase does not convey meaning Ex: “down the street” Sentence is complete thought Ex: “I went down the street.” Expression is a mathematical “phrase” Ex: 4+3 Equation mathematical “sentence” Ex: 4+3 = 7

Algebraic Expressions & Equations Definition: mathematical expressions and equations the use a variable Example of algebraic expressions: 4x + 7 7y 2 + θ α / 6σ Cannot be solved; only simplified if possible Ex: 4 + 9 – b 13- b Example of algebraic equations: 4x + 7 = 9 7y = 49 2 + θ = 45 α/6σ = 546 Can be solved to determine the value of the variable Ex: 3x =12 x = 4

Lesson Objectives (A.3a;A.3b): Define the purpose of Algebra Simple way of expressing a question to enable you to find the answer faster Define Algebra The part of mathematics in which letters and other symbols are used to represent unknown numbers and quantities in formulas and equations. Define variable A symbol (frequently a letter) used to represent an unknown value Define algebraic expression A mathematical “phrase” in which letters and other symbols are used to represent unknown numbers and quantities (Does not convey meaning!) Define algebraic equation A mathematical “sentence” in which letters and other symbols are used to represent unknown numbers and quantities (complete thought!)